Cyan inkjet ink having improved print quality with porous photo media

ABSTRACT

The present invention relates to cyan dye-based inkjet inks having improved permanence when jetted onto porous photo media. The inkjet ink includes a copper phthalocyanine dye having sulfonylamine groups, at least three co-solvents comprising about 18% to about 24% of the composition of the ink by weight, a penetrant, at least one wetting agent, and water.

CROSS REFERENCE TO RELATED APPLICATIONS

Not applicable.

MICROFICHE APPENDIX

Not applicable.

GOVERNMENT RIGHTS IN PATENT

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to inkjet inks, and, more particularly, tocyan inkjet inks having improved print quality with porous media.

2. Description of the Related Art

Thermal inkjet printing, to which this invention relates, is a commonlypracticed form of printing. Thermal inkjet printing involves intenseheating of an aqueous ink in a small amount in contact with a heatingelement so the ink is vaporized. The vaporized ink, including solids inthe ink, is then expelled through a nozzle and subsequently jetted to anintended substrate, such as, for example, paper.

The composition of an inkjet ink is traditionally comprised of deionizedwater, a water-soluble organic solvent, and a colorant. The colorant maybe a soluble dye or insoluble pigment. Traditionally, pigment based inksmay have some disadvantages as compared to dye based inks as traditionalpigment based inks tend to have slightly higher solids and viscositywhich may pose to be more difficult for jetting through relativelysmaller nozzle printhead designs. For example, due to the insolubilityof pigments in water, polymeric dispersants and/or surfactants aretypically added to improve the dispersibility of the pigment. Theaddition of a polymeric dispersant can increase the viscosity of an ink,and a viscous ink may be more difficult to jet in a printhead.

Inkjet printers may use dye-based color inks or pigment-based colorinks. Dye-based color inks tend to be more saturated and more robust toinkjet pens. In contrast, pigment-based color inks tend to be morepermanent and of the quality typically recognized with laser-likeprinters.

There is a very limited choice of pigments for use with pigment-basedcolor inks, whereas the number of dyes to be used with dye-based colorinks continuously grows.

A current challenge in the industry is to develop faster dryingdye-based inks for use with porous photo media, rather than for use withtraditional swellable polymer photo media. However, porous photo mediaare comprised of inorganic materials that, in conjunction with ozonegasses and light, interact with dyes such that the dyes fade anddegrade.

What is needed in the art is a cyan dye-based inkjet ink that may beused with porous photo media with substantially minimal fading anddegradation of the cyan dye.

SUMMARY OF THE INVENTION

Exemplary embodiments of the present invention provide an inkjet inkcomprised of a copper phthalocyanine dye having sulfonylamine groups, atleast three co-solvents comprising about 18% to about 24% of thecomposition of the ink by weight, a penetrant, at least one wettingagent, and water.

Various other exemplary embodiments of the present invention include amethod of printing using an inkjet ink. The method is comprised of thesteps of positioning a porous photo medium substantially adjacent to aprinter having a print head retaining an inkjet ink, wherein the inkjetink is comprised of a copper phthalocyanine dye having sulfonylaminegroups, at least three co-solvents comprising about 18% to about 24% ofthe composition of the ink by weight, a penetrant, at least one wettingagent, and water. The inkjet ink is then jetting from the print headonto the porous photo medium.

DETAILED DESCRIPTION OF THE INVENTION

Porous photo media, as opposed to traditional swellable polymer photomedia, tends to allow for faster drying. As such, it is desired todevelop dye-based inks that allow greater permanence with the porousphoto media. However, as noted above, porous photo media are comprisedof inorganic materials that, in conjunction with ozone gasses and light,interact with dyes such that the dyes fade and degrade.

Permanence, as used herein, refers in part to the ability of a dye toresist the interactions with light, ozone, temperature, and humiditythat cause fading and degradation of the dye associated with the media.

It has been found that a color inkjet ink comprised of a copperphthalocyanine dye having sulfonylamine groups, three co-solvents, apenetrant, and a wetting agent has an increased permanence when usedwith porous photo media.

In exemplary embodiments, the inkjet ink may further be comprised of abiocide, such as, for example, PROXEL® GXL (available from ArchChemicals, Inc. of Norwalk, Conn.).

In the various exemplary embodiments of the present invention, a copperphthalocyanine dye having sulfonylamine groups comprises about 3.0% toabout 6.0% of the composition of the ink by weight. The sulfonylaminegroups assist in enabling the cyan dye to be more stable to interactionswith ozone.

The a copper phthalocyanine dye having sulfonylamine groups may beselected from, for example, Fuji PROJET® Cyan GLF (available fromFujifilm Imaging Colorants Limited) or Nippon Cyan JPD LM-1 Liquid(available from Nippon Kayaku Co, Ltd. of Tokyo, Japan).

The at least three co-solvents are selected from the group consisting of1,3-propanediol; 1,2-alkanediol; 1,5-pentanediol; triethylene glycol;and dipropylene glycol.

In exemplary embodiments, at least two of the three co-solvents arealkanediols and the third co-solvent is a glycol.

The penetrant is preferably about 1.0% to about 3.5% of the compositionof the ink by weight. A exemplary penetrant is 1,2-hexanediol.

It is preferred that the wetting agent be of about 0.5% to about 1.5% byweight of the inkjet ink. In a more preferred embodiment, the non-ionicsilicone surfactant is about 0.75% by weight of the inkjet ink.

Exemplary wetting agents include polyoxyethylene dimethyl siloxanes,ZONYL® fluorosurfactants, and combinations thereof. A commerciallyavailable wetting agent is, for example, SILWET® L-7600 (polyalkyleneoxide grafted polydimethylsiloxane from Momentive Performance).

The polymeric dispersant is preferably about 0.5% to about 2.0% byweight of the inkjet ink, and assists in stabilizing the carbon blackpigment and buffering the pH of the inkjet ink.

An optional polymeric dispersant can be added to assist in stabilizingthe compatibility with a carbon black pigment ink in aCyan-Magenta-Yellow-Black (CMYK) inset. When CMYK inks are printed insubstantially close proximity to each other, each ink needs to becompatible and not destabilize adjacent inks. In the present exemplaryembodiments, the CMY dye inks may be printed along with a blackpigmented ink without destabilizing any of the CMY dye inks or the blackpigmented ink due to the presence of the polymeric dispersant in the CMYdye inks.

In exemplary embodiments of the present invention, the polymericdispersant may be selected from dispersants set forth in, for example,any of U.S. Pat. Nos. 5,719,204; 5,994,427; 6,063,834; 6,267,807;6,896,724; and 6,984,701, all incorporated by reference.

One or more buffers may also be included in the inkjet ink composition.Exemplary embodiments of the one or more buffers include triethanolamine(TEA), N,N-bis(2-hydroxyethyl)tuarine orN,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES), orcombinations thereof.

Several exemplary inkjet inks according to the present invention wereformulated and evaluated using a standard printhead and porous photopaper in the form of Perfectfinish Glossy Photo Paper (available fromLexmark International, Inc. of Lexington, Kentucky). The same printingwas conducted using a commercially available cyan dye-based inkjet ink.Each ink was evaluated for its permanence against the effects of ozoneand xenon light.

In Table 1, the permanence of each dye-based ink on porous photo mediais compared. The numbers shown represents the number of years ofpermanence according to the criteria of 40% density loss and assumingthe exposure level of 78 ppm-hr/yr for ozone and 1.1 Mlux-hr/yr forlight fade.

TABLE 1 Permanence of Dye with Porous Photo Media Years of Permanenceafter Exposure to: Ozone Xenon LF Ink (1 ppm or 5 ppm) (80 klux) CyanInkjet Ink 4 40 Commercially Available Cyan- 1 26 dye Based Inkjet Ink

As clearly illustrated above, the present cyan-dye based inkjet inkshows an improvement in permanence when exposed to ozone four timesgreater than that of commercially available cyan-dye inkjet inksundergoing the same exposure. When exposed to xenon light, the cyaninkjet ink of the present invention showed a permanence one and a halftimes greater than that of a commercially available cyan-dye inkjet ink.

While this invention has been described with respect to at least oneembodiment, the present invention can be further modified within thespirit and scope of this disclosure. This application is thereforeintended to cover any variations, uses, or adaptations of the inventionusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this invention pertains andwhich fall within the limits of the appended claims.

1. An inkjet ink comprising: a copper phthalocyanine dye havingsulfonylamine groups; at least three co-solvents comprising about 18% toabout 24% of the composition of the ink by weight; a penetrant; at leastone wetting agent; and water.
 2. The inkjet ink according to claim 1,wherein the a copper phthalocyanine dye having sulfonylamine groupscomprise about 3.0% to about 6.0% of the composition of the ink byweight.
 3. The inkjet ink according to claim 1, the copperphthalocyanine dye having sulfonylamine groups is selected from PROJET®Cyan GLF or Nippon Cyan JPD LM-1 Liquid.
 4. The inkjet ink according toclaim 1, wherein the penetrant comprises about 1.0% to about 3.5% of thecomposition of the ink by weight.
 5. The inkjet ink according to claim1, wherein the at least three co-solvents are selected from the groupconsisting of 1,3-propanediol; 1,2-alkanediol; 1,5-pentanediol;triethylene glycol; and dipropylene glycol.
 6. The inkjet ink accordingto claim 1, wherein two of the at least three co-solvents arealkanediols and the third co-solvent is a glycol.
 7. The inkjet inkaccording to claim 1, wherein the wetting agent is about 0.5% to about1.5% of the composition of the ink by weight.
 8. The inkjet inkaccording to claim 1, wherein the wetting agent is selected from thegroup consisting of polyoxyethylene dimethyl siloxanes, ZONYL®fluorosurfactants, and combinations thereof.
 9. The inkjet ink accordingto claim 1, further comprising one or more buffers selected from thegroup consisting of triethanolamine (TEA),N,N-bis(2-hydroxyethyl)tuarine or N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid (BES), or combinations thereof.
 10. The inkjet inkaccording to claim 1, further comprising a biocide.
 11. The inkjet inkaccording to claim 1, wherein the penetrant is a 1,2-alkanediol.
 12. Theinkjet ink according to claim 1, further comprising a dispersant asabout 0.5% to about 2.0% by weight of the inkjet ink.
 13. A method ofprinting using an inkjet ink, the method being comprised of the stepsof: positioning a porous photo medium substantially adjacent to aprinter having a print head retaining an inkjet ink, wherein the inkjetink is comprised of copper phthalocyanine dye having sulfonylaminegroups; at least three co-solvents comprising about 18% to about 24% ofthe composition of the ink by weight; a penetrant; at least one wettingagent; and water; jetting the inkjet ink from the print head onto theporous photo medium.
 14. The method of printing using an inkjet inkaccording to claim 13, wherein the copper phthalocyanine dye havingsulfonylamine groups comprise about 3.0% to about 6.0% of thecomposition of the ink by weight.
 15. The method of printing using aninkjet ink according to claim 13, wherein the copper phthalocyanine dyehaving sulfonylamine groups is selected from PROJET® Cyan GLF or NipponCyan JPD LM-1 Liquid.
 16. The method of printing using an inkjet inkaccording to claim 13, wherein the penetrant comprises about 1.0% toabout 3.5% of the composition of the ink by weight.
 17. The method ofprinting using an inkjet ink according to claim 13, wherein the at leastthree co-solvents are selected from the group consisting of1,3-propanediol; 1,2-alkanediol; 1,5-pentanediol; triethylene glycol;and dipropylene glycol.
 18. The method of printing using an inkjet inkaccording to claim 13, wherein the wetting agent is about 0.5% to about1.5% of the composition of the ink by weight.
 19. The method of printingusing an inkjet ink according to claim 14, wherein the wetting agent isselected from the group consisting of polyoxyethylene dimethylsiloxanes, ZONYL® fluorosurfactants, and combinations thereof.
 20. Themethod of printing using an inkjet ink according to claim 13, furthercomprising one or more buffers selected from the group consisting oftriethanolamine (TEA), N,N-bis(2-hydroxyethyl)tuarine orN,N-bis(2-hydroxyethyl)-2-aminoethane sulfonic acid (BES), orcombinations thereof.
 21. The method of printing using an inkjet inkaccording to claim 13, further comprising a biocide.
 22. The method ofprinting using an inkjet ink according to claim 13, wherein the inkjetink is further comprised of a dispersant as about 0.5% to about 2.0% byweight of the inkjet ink.